IANAL but my understand is that the plain view doctrine would apply.
for example, if the police have a warrant for a 2000 Honda Civic with suspicion it was used in a hit and run, they come to the property and check the cars parked in the driveway, the garage door is open so they can see no cars there as well but they come into the house, go into your basement and find your grow operation, that would constitute an illegal search.
The grow operation was not in "plain sight", since it was behind a door in the basement and the scope of the warrant was for a 2000 Honda Civic, something not kept in basements.
Usually warrants tend to be overbroad, so the it would probably be written as "search property for evidence of hit and run" in which case they could gain access to the basement.
for example, if the police have a warrant for a 2000 Honda Civic with suspicion it was used in a hit and run, they come to the property and check the cars parked in the driveway, the garage door is open so they can see no cars there as well but they come into the house, go into your basement and find your grow operation, that would constitute an illegal search.
The grow operation was not in "plain sight", since it was behind a door in the basement and the scope of the warrant was for a 2000 Honda Civic, something not kept in basements.
Usually warrants tend to be overbroad, so the it would probably be written as "search property for evidence of hit and run" in which case they could gain access to the basement.